The companion application is directed to an apparatus described as a microgun. This disclosure reveals a method of manufacturing the microgun. In particular, it describes a supportive substrate, a pyramid field emission device, suitable anodes cooperative with it to define an electron optical system for formation of a beam. The various anodes are manufactured in selected layers by semi-conductor type batch manufacturing process which may simultaneously fabricate on the same supportive substrate the necessary integrated circuits to control the electron optical elements. This method further relates to a procedure whereby a cermet material is selectively shaped and placed on a supportive substrate to define an electron emitting member, and in conjunction with subsequently formed anodes, thereby yields a microgun assembly.
Methods of fabricating field emission devices have been described in the following references:
(A) Spindt U.S. Pat. No. 3,755,704
(B) Spindt U.S. Pat. No. 3,789,471
(C) Spindt U.S. Pat. No. 3,812,599
(D) Spindt Journal of Applied Physics, Vol. 47, No. 12, 1976
(E) Fraser U.S. Pat. No. 3,753,022
(F) Redman U.S. Pat. No. 3,982,147
(G) Levine U.S. Pat. No. 3,921,022
(H) Oess U.S. Pat. No. 3,935,500
(I) Fukase U.S. Pat. No. 3,998,678
Regarding these prior art devices, they all appear to employ metallic emitters with one or more electron optical elements. The several references of Spindt disclose and describe a device having relatively large size, typically in the range of about 0.1 millimeter square dimensions. Moreover, this is accomplished without optical elements for deflection and focus. Fraser follows Spindt and adds electron optical elements, which elements must be mechanically aligned and therefore which suffer from inaccuracies of alignment. Mechanical alignment inaccuracies are probably the major cause of fabrication failure in semiconductor processes, thereby yielding the most severe form of distortion. Accordingly, Fraser is therefore severely limited in the manufacture of an economical field emission device. Redman requires similar mechanical alignment and limits the number of emitters which can be fabricated in an array because of the same problems of Fraser. Levine requires mechanical alignment of successive layers, thereby compounding the probability of misalignment in the fabrication of the finished product. Oess is probably the most susceptible to mechanical problems in fabrication and has the highest probability of misalignment. The various prior art devices produce emitting services which have large and relatively limited random emitting sites on the surface. This inevitably creates substantial noise. In like fashion, all the prior art references are limited in the ability to fabricate an unlimited number of microgun structures over an unlimited area to take advantage of the economies obtained in the batch fabrication procedure disclosed herein.